A $\mathcal{M}\gtrsim 3$ shock in `El Gordo' cluster and the origin of the radio relic

Abstract

We present an X-ray and radio study of the famous `El Gordo', a massive and distant ($z=0.87$) galaxy cluster. In the deep (340 ks) Chandra observation, the cluster appears with an elongated and cometary morphology, a sign of its current merging state. The GMRT radio observations at 610 MHz reveal the presence of a radio halo which remarkably overlaps the X-ray cluster emission and connects a couple of radio relics. We detect a strong shock ($\mathcal{M}\gtrsim 3$) in the NW periphery of the cluster, co-spatially located with the radio relic. This is the most distant ($z=0.87$) and one of the strongest shock detected in a galaxy cluster. This work supports the relic-shock connection and allows to investigate the origin of these radio sources in a uncommon regime of $\mathcal{M}\gtrsim 3$. For this particular case we found that shock acceleration from the thermal pool is still a viable possibility.

10 pages, 8 figures, 2 tables; Updated to match the accepted version in MNRAS; Results unchanged

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Cited by in corpus (7)

• Deep VLA observations of the cluster 1RXS J0603.3+4214 in the frequency range 1-2 GHz
• ALMA-SZ Detection of a Galaxy Cluster Merger Shock at Half the Age of the Universe
• Observations of the galaxy cluster CIZA J2242.8+5301 with the Sardinia Radio Telescope
• A Study of High-redshift AGN Feedback in SZ Cluster Samples
• Diffuse radio emission in MACS J0025.4$-$1222: the effect of a major merger on bulk separation of ICM components
• The correlation between radio power and Mach number for radio relics in galaxy clusters
• Complex diffuse emission in the $z=0.52$ cluster PLCK~G004.5-19.5